How can I include the backslash character in a Python list?

Question

When I try to include the backslash character in a list in Python,

>>> lst = ['\']
  File "<stdin>", line 1
    lst = ['\']
              ^
SyntaxError: EOL while scanning string literal

How can I include a backslash character without causing the above error?

Try `'\\'` - the first backslash escapes the second – Michael Delgado May 27 '20 at 06:10 — Michael Delgado, May 27 '20 at 06:10

score 2 · Accepted Answer · answered May 27 '20 at 06:17

2

The problem has nothing to do with the list. What is broken in your snippet is just a string literal. Easiest way to reproduce would be something like print('\'). It happens because certain symbols needs to be escaped in strings. For instance, if you want to encode a new line symbol in a string, you could do it as follows print('foo\nbar') and \n here means a line delimiter symbol. Notice, that its a compound symbol and \ is used as its first part.

So, getting back to your example, what is really happening is you are trying to escape the following symbol after slash, i.e. the single quote. And you succeed! However, then the whole string literal starts missing the closing quote. How to fix it? Escape the escape symbol:

lst = ['\\']

answered May 27 '20 at 06:17

Ivan Velichko

6,348
6
44
90

Your suggestion produces ['\\'] but i need ['\'] – Voiceroy May 27 '20 at 06:20
Well, it doesn't. Try `print(len(lst[0))`. It shows `1`. The formatter just uses the same escaping technique while printing it out. – Ivan Velichko May 27 '20 at 06:21
For contrast, try the following list: `lst = ['\\\\']; print(lst, len(lst[0]))`. It would output 2, even though the string looks like it has 4 slashes. – Ivan Velichko May 27 '20 at 06:23

How can I include the backslash character in a Python list?

1 Answers1